The invention concerns a cover of the type defined in the introductory portion of claim 1.
The DK published Application No. 151,734B, see in particular FIGS. 4 and 5 of the drawing and the associated part of the description, discloses a cover of this type, where the mask flap is disposed at the side edge of the cover where the holes are arranged. When such a cover together with several others of the same type is placed in a ring file, the mask flap will be positioned in the vicinity of the back of the ring file, and will thus not be readily visible when the contents of the ring file are rapidly leafed through. Furthermore, with this known structure it is not easy to place notes on the side of the mask flap which faces upwardly during the use of the cover in a projector, since this normally requires opening of the ring file and removal of the cover which is to be provided with notes on the mask flap side in question.